Once you’ve conquered your fear of static electricity and successfully built a kick ass custom PC from the ground up, making the jump to custom electronics isn’t all that intimidating. The open-source Arduino microcontroller breaks down the entry barrier even further. Flexible, powerful, easy-to-use and licensed-to-alter (under Creative Commons Share-Alike), the Arduino is the linchpin behind scads and scads of nifty DIY electronics projects. And hey! It just so happens that we’ve gathered 25 of the coolest, craziest, and most useful Arduino-powered projects in this gallery for your viewing – and building – pleasure. Mind-controlled Nerf guns, anybody? No, it’s not black magic. It’s the magic of Arduino!

Give any geek a box of Legos and he’s bound to have a good time. While we love slapping together robotic creations made possible by those nifty Lego Mindstorms sets, our ability to come up with badass constructions is admittedly a bit weak. Frankly, we’d be lost without the instruction manual. One enterprising Lego fanatic named Plum B doesn’t suffer from our lack of creativity and engineering know-how, though; he just unveiled a life-sized, fully operational Lego replica of the chainsaw-sporting Lancer assault rifle from Gears of War.

As vast as the internet can be, there comes a time in every web surfer’s life when there’s just nothing left to browse. Well, nothing interesting at least. After visiting your favourite online haunts, playing a few web games, chatting it up on Twitter or Google+ and seeking out behind-the-scenes dirt and spoilers for a few of your favorite films, it’s easy to run out of ideas as to what you should scope out next. In such a dire situation, you could take the quitter’s way out and head outside to enjoy everything that Mother Earth has to offer, or you can buckle in for a trip to the Museum of Online Museums, our Cool Site of the Week.